Forced-draft and damper regulator for steam-boilers.



No. 684,584. Pa ten'tad Oct. [5, 1901. E. McLEAN.

FORGED DRAFT AND DAMPER REGULATOR FOR STEAM BUTLERS.

(Application filed. Dec. 31, 1900;)

(No Model.)

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PATENT FORCED-DRAFT AND DAMPER REGULATOR FOR STEAM-BOILERS.

SPEGIIEIGATIQN forming part of Letters Patent No, 684,584, dated October1 5, 1901.

application filed December 31, 1900. Serial No. 41,621. (No model.)

To all whom it may concern:

Beit known that I, EMBURY MCLEAN, a citizen of the United States,residing in the bor-' ough of Brooklyn, city of New York, State of NewYork, have invented certain new and useful Improvements in Forced-Draftand Damper Regulators for Steam Boilers, of which the following is aspecification.

The object of this invention is to control the forced-draft blower andthe damper by direct application of the pressure of steam from theboiler and to do this in such a Way that the damper may at will, byadjustment of the apparatus, be held closed until the speed of theblower has increased from its minimum speed or condition of substantialinactivity to a predetermined rate of speed, when the damper is thenautomatically opened;

In carrying out my invention I employ a forced-draft apparatusconsisting of a motor and associated blower for delivering a forceddraft beneath the grate-bars. Steam from the boiler is conducted to theblower-motor through a pressure-regulator or reducingvalve to controlthe steam-pressure to drive the motor at the desired maximum speed. Inthis pipe I also place a cut-oft or controller device connected with thesteam-space of the boiler and acting to entirely cut off steam from thereducing-valve and blower-engine when the normal working pressure in theboiler is exceeded. In connection with this controller or cut-off andreducing valve I employ also a by-pass pipe, which is provided with apressure-regulator or reducing-valve, through which a minimum quantityof steam is admitted to the blower-motor to keep it in motion at aminimum speed when the main supply of steam is cut off from it. Aby-pass is not essential in the working of such an apparatus, as theblowing-motor may be entirely arrested when the steam is cut off asdescribed; but I prefer to employ it for then maintaining the motor inaction at a minimum speed, as it is desirable for well-understoodpractical reasons. The arrangement I have described is one Well known.In connection with such an apparatus it has been proposed to control thedamper in the flue or stack, so as to close it when the main steamsupplyis cut off from the motor and the blower is running at minimum speed andopen it when steam is restored to the motor and the speed of the blowercommences to accelerate. My invention does not therefore contemplate,broadly, such an operation, but consists in the following organizationemployed in association with the blower organization which has beendescribed.

From the steam-pipe between the reducingvalve and the blower-engine Itake a connection for admitting steam to one side of a diaphragm motoror controller, with which is connected a lever or other suitableappliance for actuating the damper, the arrangement of course being suchthat when the blower-mofor is receiving steam freely through its mainsteam-pipe connection the pressure of steam in the diaphragm-dampercontroller will be exerted thereupon in such a Way as to open thedamper. By providing an adj ustable weight or weights or otheradjustable device or appliance acting to close the damper and to opposethe actuation of the diaphragm-motor to open it I may cause the damperto be opened when the blower has reached a predetermined speed. Theadvantages of such an arrangement are that the speed of the blower maybe increased from its minimum speed up to the desired predeterminedpoint, and the damper being closed the hot gases are held in the furnaceuntil the speed of the.

blower has reached a point at which it is desirable that the dampershould be opened. The arrangement is one which experience hasdemonstrated to be a most satisfactory and economical one.

The accompanying drawing is a diagrammatic View illustrating theinvention.

A represents the fire-box or combustionchamber of the furnace, and A" aconduit opening at one end into the space beneath the grate-bars, thearea of the opening being regulated by an adjustable valve A as iscommon. The opposite end of the conduit is connected with a blower, as acommon Root blower B, driven by a steam-engine 0, connected with theboiler by a pipe D, in which is a reducing-valve D and a regulator orcutoff valve E, also connected with the steamspace of the boiler.Aby-pass or shunt pipe F, containing a pressure-regulating Valve F, isconnected around the cut-off valve E and the main reducing-valve D.l/Vhen steam in the boiler is below desired pressure, the blower-enginereceives steam through the reducing-valve D and the blower is driven ataccelerated speed. When the desired working pressure is exceeded, thecut-off valve E is actuated to arrest the passage of steam through thereducing-valve. At this time the by-pass pipe delivers a minimumquantity of steam to the blower-engine, which is then driven at itsminimum speed. As before stated, this is an organization that is commonand well understood. From the main steam-pipe, between thereducing-valve D and the blower-engine, I run a steam-pipe G to theunder side of the diaphragm h of a diaphragm-motor or controller H, ofcommon construction. The opposite side of the diaphragm is connectedwith a lever I, pivoted at one end at t' and at its other end jointed toa rod K, connected with the damper L in the flue or stack M. On thelever I is a sliding weight 0, held in any desired position by aset-screw 0. When the desired working pressure in the boiler is exceededand the speed of the blower reduced to a minimum, the weight 0 acts toclose the damper L. "When the pressure in the boiler falls, the cut-offvalve opens and steam through the main supply-pipe again commences topass to the blower-engine and the speed of the blower is accelerated.The damper need not open at once; but by the proper disposition of theweight 0 upon the lever I its opening may be delayed until the pressurein the pipe G has risen so as to be sufficient to actuate the diaphragmof the motor II against the resistance of the weight to open the damper,and such pressure would correspond, substantially, with a given speed ofrotation of the blower. The moment of opening the damper may thereforebe adjusted at will. This mode of operation is due to the fact that witha proper weighting of the lever I the diaphragm h will not be actuatedby the steam-pressure in thepipe G while the blower-engine is onlyreceiving the minimum quantity of steam and is running at minimum speed.WVhen, however, steam again passes through the Valve D, an appreciableinterval of time (depending upon the resistance applied to the lever I)will elapse before the pressure in pipe G rises sufficiently to actuatethe diaphragm, and during such period the speed of the blower-motor willbe accelerated, and the time of opening of the damper will substantiallycorrespond with a given speed of the blower. By suitably regulating theresistance applied to the lever I the time of opening of the damper maywithin limits be determined.

I prefer to use an adjustable weight instead of an adjustable spring, asI think it is more reliable in action.

I do not limit myself to the specific construction described, asobviously the same results and mode of operation may be accomplished bythe use of other apparatus per forming the same offices or functions asthat described.

There are nowin the market and well known valves, such as the Fostervalve, which combine all the functions of the parts marked D E F F inthe drawing and which are commonly used in lieu of them--that is to say,a valve which when the desired pressure in the boiler is exceededpermits only a minimum quantity of steam to pass and which also acts asa reducing-valve. I have shown the three valves D E F and by-pass Fmerely as one form ofapparatus that I may employ.

I claim as my invention-- 1. In a forced-draft and damper regulatorapparatus the combination with the boiler and furnace of a blower, itsengine, a steam connection from the boiler to the engine,pressure-reducing and cut-off valve mechanism in said steam connection,a damper-motor, a steam connection extending from the dampermotor to thesteam connection of the blowenengine and connected therewith betweensaid engine and said valve mechanism, the damper, and an operativeconnection between the damper and its motor, for the pur pose set forth.

2. In a forced-draft and damper regulator apparatus the combination withthe boiler and furnace of a blower, its engine, a steam connection fromthe boiler to the engine, pres sure-reducing and cut-off valve mechanismin said steam connection, a damper-motor, a steam connection extendingfrom the dampermotor to the steam connection of the blower engine andconnected therewith between said engine and said valve mechanism, thedamper, a lever connection between the damper and the damper-motor and adevice applied to said lever acting to oppose the actuation of saidmotor by the steam-pressure to open the damper, for the purpose setforth.

3-. In a forced-draft and damper regulator apparatus the combinationwith the boiler and furnace of a blower, its engine, a steam connectionfrom the boiler to the engine, pressure-red ucin g and cut-off Valvemechanism in said steam connection, a damper-motor,- a steam connectionextendingfrom the dampermotor to the steam connection of theblowenengine and connected therewith between said engine and saidvalve'meoha'nism, a damper,- a lever connection between the damper andits motor, and an adjustable device applied to said lever to opposeactuation of the damper-motor by the steam-pressure to open the damper.

4. In a forced-draft and damper regulator apparatus the combination withthe boiler and furnace of a blower, its engine, a steam connection fromthe boiler to the engine, pressure-reducing and cut-ofi valve mechanismin said steam connection, a damper-motor, a steam connection extendingfrom the dampermotor to the steam connection of the blowerengine andconnected therewith between said too engine and said valve mechanism, adamper, a lever connection between the damper and its motor and anadjustable weight applied to said lever to oppose actuation of thedamper-motor by the steam-pressure to open the damper.

5. In a forced-draft and. damper regulator apparatus the combinationwith the boiler and furnace of a blower, its engine, a steam connectionfrom the boiler to the engine, pressure-reducing and cut-01f valvemechanism in said steam connection, a damper-motor, a steam connectionextending from the dampermotor to the steam connection of theblowerengine and connected therewith between said engine and said valvemechanism, a damper, a lever connection between the damper and its motorand a sliding weight applied to said EMBURY' MOLEAN.

Witnesses:

KATHARINE MAOMAHON, EDWARD O. DAVIDSON.

